Robot for transfer of glass

ABSTRACT

Disclosed is a robot for transferring a substrate, wherein the robot has a robot arm, a hand part, which includes a plurality of plates. A plurality of pins protrude from the plates such that each pin may be folded downward. The pins include a rubber or resin with thermally insulating properties. By selectively folding down a certain number of the pins, contact may be minimized between the substrate and the robot, thereby preventing damage to the substrate such as thermally-induced defects and stains.

This application claims the benefit of the Korean Application No.P2004-49514 filed on Jun. 29, 2004, which is hereby incorporated byreference as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a robot for transfer of glass, and moreparticularly, to a robot for transfer of glass that prevents stains anddefects caused by a robot hand.

2. Discussion of the Related Art

Liquid Crystal Display (LCD) devices have become widely used due toadvantageous characteristics such as compact size, thin profile, and lowpower consumption. As such, LCDs have become substitutes for Cathode RayTube (CRT) displays.

In general, the LCD device includes an LCD panel, wherein the LCD panelincludes a thin film transistor substrate, a color filter substrate, anda liquid crystal layer. The thin film transistor includes a gate line, adata line, a thin film transistor, and a pixel electrode. The gate linecrosses the data line at the right angle, thereby defining a pixelregion. The thin film transistor and the pixel electrode are formed inthe pixel region. The color filter substrate generally includes a colorfilter layer and a common electrode. The liquid crystal layer is formedbetween the thin film transistor substrate and the color filtersubstrate.

A method for fabricating the LCD device generally includes threeprocesses: a substrate fabrication process, a cell process, and a moduleprocess.

The substrate fabrication process includes two steps of forming a thinfilm transistor array and forming a color filter array. In the step offorming the thin film transistor array, a plurality of thin filmtransistors and pixel electrodes are formed on a lower substrate. In thestep of forming the color filter array, a color filter layer of R, G andB is formed on an upper substrate having a black matrix layer by usingpigment or dye, and a common electrode of ITO is formed on the uppersubstrate.

During the cell process, spacers are formed between the lower substratehaving the thin film transistor array and the upper substrate having thecolor filter array, to maintain a cell gap between them. Then, the twosubstrates are bonded to each other, and liquid crystal is injectedbetween the two substrates, thereby forming an LCD panel having aplurality of cells.

In the module process, the LCD panel is connected with a signalprocessing circuit to form an LCD device.

To fabricate the LCD device through the substrate fabrication process,the cell process and the module process, it is necessary to load thesubstrate into various equipment, or to unload the substrate from theequipment in order.

Also, since it is impossible to stop the fabrication process line due tosome defects of the equipment, a plurality of substrates are movedtogether using a cassette for temporarily storing the substrates.Accordingly, the plurality of substrates are loaded into the cassette bya transfer robot and unloaded from the cassette by the transfer robotaccording to the predetermined order.

FIG. 1 is a perspective view of a transfer robot according to therelated art.

As illustrated in FIG. 1, the transfer robot 50 according to the relatedart includes a main axis 51, a robot arm 52, and a hand part 53. Therobot arm 52 is mounted on the main axis 51 allowing it to rotate,wherein the robot arm 52 may also move in parallel, fold, or extend. Thehand part 53 is provided in the fore end of the robot arm 52, whereinthe substrate 15 is loaded on the hand part 53.

In the transfer robot 50 having the aforementioned structure, thesubstrate 15 is unloaded from the cassette (not shown) by the robot arm52. Then, the substrate 15 is loaded on the hand part 53, and thesubstrate 15 is loaded on a stage 25 by rotation of the hand part 53.The stage 25 is positioned on an opposite side to the cassette (notshown). A plurality of lift pins 26 are provided in the stage 25,wherein the lift pins 26 move up and down. If the substrate ispositioned on the stage 25 by the rotation of the robot arm 52, the liftpins 26 are moved upward, whereby the substrate 15 is separated from therobot arm 52. After separating the substrate 15 from the robot arm 52,the lift pins 26 are moved downward so that the substrate 15 is loadedonto the stage 25.

When the substrate 15 is stored in the cassette, the substrate 15 may beoriented at a slant or may be straight. Accordingly, the robot 50 sensesand compensates for the position and orientation of substrate 15(X-axis, θ-axis, the traveling axis) when loading the substrate 15,whereby the substrate 15 is loaded on the stage 25 at the correctposition.

Referring to FIG. 1, the X-axis is defined along the direction of motionfor forwarding the substrate toward the stage 25. The 9-axis is definedby the rotation to make substrate 15 and the stage 25 in parallel whenthe plane surface of the substrate 15 is otherwise diagonal to the planesurface of the stage 25. The traveling axis is defined as the directionof translation along the θ-axis, and may be orthogonal to the X-axis.Motion along the traveling axis is for aligning the substrate 15 withthe stage 25 when the substrate 15 is positioned at the side of thestage 25.

To sense the position of the substrate 15, the hand part 53 of thetransfer robot 50 has first and second sensors 54 and 55. The first andsecond sensors 54 and 55 sense the position state of the substrate 15.For example, the first and second sensors 54 and 55 detect the positionof the substrate 15 relative to the X-axis and θ-axis. Accordingly, thetransfer robot 50 senses the correct position of the substrate 15, andaligns the substrate 15 according to a compensation value, and thenloads the substrate 15 on the stage 25.

FIG. 2 illustrates a hand part 53 of a related art robot fortransferring a substrate. As illustrated in FIG. 2, the hand part 53 isprovided with a connector 34, a plurality of plates 38, and a pluralityof pads 39. One side of the connector 34 is connected with the robot arm52 of FIG. 1. The plurality of plates 38 are arranged along onedirection at fixed intervals at the other side of the connector 34. Theplurality of pads 39 protrude from the upper surface of each of theplates 38. The plurality of pads 39 are formed of rubber to fix thesubstrate 15 by a vacuum force.

The related art robot for transferring a substrate has the hand part 53,wherein the hand part 53 is provided at the fore end of the robot arm 52so that it can be rotated, translated, and extended. Also, the hand part53 has the plurality of pads 39, wherein each of the plurality of pads39 includes a ring-shaped sidewall for fixing the loaded substrate.

FIG. 3 illustrates the pad 39 of FIG. 2. As illustrated in FIG. 3, eachof the pads 39 is formed of a main body having a circle-shaped bottom.The pad 39 includes a sidewall 41 and a bottom 42. A hole 43 of thepredetermined diameter is formed in the center of the bottom 42.Although not shown, the vacuum device is additionally provided to supplythe vacuum force to the pad 39.

When the substrate 15 is loaded on the hand part 53, the vacuum force isprovided to the pad 39, whereby the substrate 15 is fixed to the pad 39.Then, the substrate 15 is transferred to the next process.

However, the robot for transferring substrates according to the relatedart has the following disadvantages.

When the substrate is in contact with the pads 39 after a baking processof 200° C. or more, an amount of heat from the substrate is conducted tothe pad 39, causing a localized temperature drop on the substrate.Accordingly, the contact efficiency is lowered on the portions of thesubstrate having the temperature drop. After etching the substrate aftera development process, the portions of the substrate subject to thetemperature drop may have the various defects such as an adhesionfailure in the respective layers of array, rolling, and thermal images.

Especially, as the substrate has the thin profile, an amount of heat iseasily transmitted from the surface of the substrate to the pad 39.Thus, the yield may be lowered due to the defects such as a thermalimage.

Accordingly, as the substrate is fixed to the pad by the vacuum force,ring-shaped prints are formed on the substrate due to the sidewall ofthe pad. The ring-shaped prints of the substrate may cause a thermalimage along with the mechanical deformation due to thermal expansion andcontraction.

In addition, stains may be generated on the substrate due to the use ofpads. Especially, when loading the substrate spin-coated with aconductive material, stains can be generated on the substrate, therebylowering the yield.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a robot for transferof glass that substantially obviates one or more of the aforementionedproblems due to limitations and disadvantages of the related art. Ingeneral, the present invention achieves this by providing a plurality ofthermally insulating pins, which may be individually folded down tominimize contact with the glass.

An advantage of the present invention is that it improves the yield ofan LCD fabrication process.

Another advantage of the present invention is that it reducesthermally-induces defects in LCD substrates.

Another advantage of the present invention is that it reduces the riskof staining a substrate during LCD fabrication.

Additional advantages of the invention will be set forth in thedescription which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theadvantages of the invention will be realized and attained by thestructure particularly pointed out in the written description and claimshereof as well as the appended drawings.

The aforementioned and other advantages of the present invention areachieved with a robot for transferring a substrate, wherein the robotcomprises a robot arm; and a hand part mounted at a fore end of therobot arm, wherein the hand part includes a connector having a sideconnected to the robot arm, a plate; and a plurality of pins disposed onan upper surface of the plate, and wherein each of the pins protrudesupward and may individually be folded downward.

In another aspect of the present invention, the aforementioned and otheradvantages are achieved by a method of manufacturing an LCD module,which comprises forming a plurality of thin film transistors and pixelelectrodes on a first substrate; providing a second substrate; bondingthe first substrate to the second substrate; and injecting a liquidcrystal between the first and second substrates, wherein forming aplurality of thin film transistors and pixel electrodes includesunloading the first substrate from a cassette using a robot having aplurality of pins, wherein unloading the first substrate includes:selecting a subset of pins from the plurality of pins for contacting thesubstrate, wherein selecting is based on the temperature sensitivity ofthe substrate; folding down a remaining subset of pins from theplurality of pins; and placing the first substrate in contact with thesubset of pins.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

FIG. 1 is a perspective view of a related art robot for transferringglass;

FIG. 2 is a detailed view of a hand part of a related art robot fortransferring glass;

FIG. 3 is an expanded view of a pad part of FIG. 2;

FIG. 4 is an expanded view of an exemplary hand part in a robot fortransfer of glass according to the present invention; and

FIG. 5A and FIG. 5B are expanded views of a pin of FIG. 4.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Reference will now be made in detail to embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

Hereinafter, a robot for transferring glass according to the presentinvention will be described with reference to the accompanying drawings.

FIG. 4 is an expanded view of an exemplary hand part of a robot fortransfer of glass according to the present invention.

As illustrated in FIG. 4, the hand part 100 of the robot fortransferring glass according to the present invention is provided with aconnector 101, a plurality of plates 102, a plurality of pins 103, andguides 105. The hand part 100 is mounted to the fore end of a movablerobot arm (not shown) so that it may be rotated and extended. Asubstrate G may be loaded on the hand part 100. The connector 101connects the robot arm with the hand part 100, whereby one side of theconnector 101 is connected to the robot arm. The plurality of plates 102(also referred to as support plates) are formed at the other side of theconnector 101, wherein the plurality of plates 102 are formed in onedirection at fixed intervals. A plurality of pins 103 protrude from theupper surface of the respective plates 102 to fix the substrate G. Theguides 105 are formed in correspondence with four corners of thesubstrate G to prevent the substrate from being shaken.

Although the exemplary hand part described above has a plurality ofplates 102, it will be readily apparent to one of ordinary skill thatthe plates 102 may be a single plate. The plate may or may not haveopenings, and the specific shape depends on the mass of the plate andthe size and mass of the substrates to be transferred. Any suchvariation to the shape of the plate or plates are within the scope ofthe invention. Further, as used herein, the use of the term glass mayrefer to any substrate, plate, or panel, made of glass or any othermaterial, which is sensitive to thermally-induced defects.

Each of the pins 103 may be formed at the fixed interval from thelateral side of the plate 102, wherein the pins 103 may protrude upward,or be folded downward. The plate 102 is connected with each of the pins103 by supporting devices 104. The pins 103 may be formed of rubber orresin having good heat resistance, or thermally insulating,characteristics, so as to minimize thermal damage to the substrate G.

The guide 105 may be higher than the pin 103, so that it is possible toprevent the substrate from being shaken when the substrate is put ontothe pins 103.

In an exemplary robot for transferring glass according to the presentinvention, the plurality of pins 103 are formed at the predeterminedinterval from the plate 102 of the hand part 100 for loading thesubstrate. The pins 103 may be folded downward as needed. A subset ofpins 103 may be selected for contacting a substrate, depending on thesize, mass, temperature sensitivity, and the presence of a coating onthe substrate. The other pins 103 that will not contact the substrateare folded downward prior to placing the substrate on the hand part 100.Accordingly, when moving the substrate, it is possible to decrease thecontact area between the pins 103 and the substrate G.

FIG. 5A and FIG. 5B are the expanded views of the pin of FIG. 4.

As illustrated in FIG. 5A and FIG. 5B, the pins 103 may protrude upwardor be folded downward. The pins 103 are provided at a predeterminedinterval from one side of the plate 102 by supporting devices 104.

To mitigate staining of the substrate due to contact with the pins 103,the pins 103 may be folded downward. In this state, the substrate G maybe loaded and moved.

As mentioned above, the robot for transferring glass according to thepresent invention has the following advantages.

In the hand part of the robot, the pins may be folded downward.Accordingly, it is possible to minimize the contact area between thepins and the substrate, thereby preventing stains from being generatedon the substrate.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1-10. (canceled)
 11. A method of manufacturing an LCD module,comprising: forming a plurality of thin film transistors and pixelelectrodes on a first substrate; providing a second substrate; bondingthe first substrate to the second substrate; and injecting a liquidcrystal between the first and second substrates, wherein forming aplurality of thin film transistors and pixel electrodes includesunloading the first substrate from a cassette using a robot having aplurality of pins, wherein unloading the first substrate includes:selecting a subset of pins from the plurality of pins for contacting thesubstrate, wherein selecting is based on the temperature sensitivity ofthe substrate; folding down a remaining subset of pins from theplurality of pins; and placing the first substrate in contact with thesubset of pins; wherein the robot includes a robot arm and a hand partmounted at a fore end of the robot arm; wherein the hand part includes aconnector having a side connected to the robot arm, at least two platesbeing connected to the second side of the connector opposite the sideconnected to the robot arm and having supporting devices and a pluralityof guides formed at the positions on the plates corresponding to fourcorners of a substrate.